The field of cancer is undergoing a sea change, thanks to the genetics revolution that has uncovered many of the defects responsible for causing the disease. Using the latest molecular biology techniques to home in on cancer’s genetic roots, doctors are starting to halt precancerous growths before tumors ever develop and to target cancers that have already started to grow with a precision unimaginable just a decade ago.Some of the new approaches:

Gleevec shows promise against an uncommon digestive tract cancer called gastrointestinal stromal tumors. Tests of the drug are also underway in patients with lung, prostate and brain cancers.

A genetically engineered mouthwash is being tested against pre-cancerous growths that often precede oral cancer. The treatment targets a faulty p53 gene, known as a tumor suppressor.

Researchers are reporting early success with genetically engineered vaccines that activate the patient’s own immune system to attack and destroy tumors.